Study On The Photochemical Degradation Properties Of Fatty Amine Flotation Collectors

The annual wastage of flotation reagents is megaton in our country, and a mass of reagents remain in the wastewater of mineral processing. But using reagents blindly and unreasonably result in deterioration of entironment of many mine areas in recent years. The circumjacent water body and soil were subjected to serious pollution and which bring damage to the human health, agricultural production and fishery. So researching the degradation process and mechanism of flotation reagents in water body has widespread meaning to the treatment of mining wastewater.This paper drawed lessons from the advanced techniques(Fenton oxidation, photocatalytic oxidation, photochemistry oxidation and microorganism-decomposing method)in water processing to study the degradation effect and regulation of the typical fatty amine flotation collectors in water body, which mainly aimed at decyl propyl ether amide, dodecyl propyl ether amide, laurylamine and stearamine. It is shown that the four fatty amine flotation collectors are difficult to biodegrade by the experiment biodegradation properties of the reagents. The test result which through degrading fatty amine flotation collectors separate by Fenton oxidation, titanium dioxide supported on stilbite photocatalytic oxidation or UV/H₂O₂/air oxidation method indicates that UV/H₂O₂/air oxidation method which degradation rate and mineralization degree are very high is the most suitable for degrading fatty amine flotation collectors, and it reacts peaceably, operate simply, consume low energy consumption.The degradation properties of the four typical fatty amine flotation collectors were studied in the condition of amounts of H₂O₂, pH value, UV light and aeration by UV/H₂O₂/air oxidation method. It shows that UV light and aeration are the predominant factors of degrading fatty amine flotation collectors, and the effect of them is the most significant. The acidic condition is suitable for photochemistry oxidation, and the degrading effect is best when pH=4.5. The velocity of reaction was increased observably by Aeration. The degradation sequence of the four fatty amine flotation collectors which is consonant with the COD degradation sequence is following: decyl propyl ether amide＞laurylamine＞dodecyl propyl ether amide＞stearamine. The degradation rate of decyl propyl ether amide reached 100% and COD removal rate reached 78.06%. It indicates that decyl propyl ether amide is degraded easily. The amidocyanogen of the four fatty amine flotation collectors were basically converted into nitrate radical and nitrite radical by UV/H₂O₂/air oxidation method, the conversion sequence of which is following: decyl propyl ether amide＞laurylamine＞dodecyl propyl ether amide＞stearamine, consonant with the degradation sequence and the COD degradation sequence of the reagents. It shows that the organic nitrogenous of the fatty amine flotation collectors had oxidized to inorganic nitrogenous when the carbon and hydrogen of them oxidized to CO₂ and H₂O.A pseudo-first order kinetic model was adopted to represent the reaction of decyl propyl ether amide by the experiment on degradation of typical fatty amine flotation collectors. The kinetic reaction equation was fitted in this paper.The infrared absorption spectrum of decyl propyl ether amide and stearamine wastewater was depicted and mechanism of degradation of the fatty amine flotation collectors by UV/H₂O₂/air oxidation method was discussed.